The `TTI` hooks are used during vectorization for calculating register
pressure. The default implementation defined wrong value for register
number (all register class are 8 registers).
This patch also defines LoongArch's own register classes.
When we do not enable vector features, we should return the default
value (`TargetTransformInfoImplBase::getRegisterBitWidth`) instead of
zero.
This should fix the LoongArch [buildbot
breakage](https://lab.llvm.org/staging/#/builders/5/builds/486) from
#78943.
With enough codegen complete, we can now correctly report the size of
vector registers for LSX/LASX, allowing auto vectorization (The
`auto-vec` feature needs to be enabled simultaneously).
As described, the `auto-vec` feature is an experimental one. To ensure
that automatic vectorization is not enabled by default, because the
information provided by the current `TTI` cannot yield additional
benefits for automatic vectorization.
This patch only provides basic LoongArchTTIImpl, and more hooks
will be added to provide TTI machinery for LoongArch soon.
Reviewed By: SixWeining, xen0n
Differential Revision: https://reviews.llvm.org/D147524
This patch only provides basic LoongArchTTIImpl, and more hooks
will be added to provide TTI machinery for LoongArch soon.
Reviewed By: SixWeining, xen0n
Differential Revision: https://reviews.llvm.org/D147524
